After three months of releasing photos and data piecemeal, scientists with NASA’s New Horizons mission codified their preliminary observations of Pluto and three of its moons in the Oct. 16 Science. Here are five key (though not necessarily brand-spanking new) findings in the paper that epitomize the surprising complexity of the Pluto system:

1. Pluto has mountains of ice several kilometers high.
Over the years astronomers had gathered evidence that Pluto’s surface is covered with nitrogen, carbon monoxide and methane ice. But those compounds can’t support the towering mountains seen in the pictures New Horizons sent back, leading researchers to conclude that the ices sit atop solid bedrock of frozen water.

2. Pluto likes to resurface.
Scientists spotted evidence of dynamic surface processes familiar to Earthlings such as glaciation and tectonic movement of the crust. A large portion of Pluto’s famous heart-shaped region has no visible craters, which indicates it is no more than a few hundred million years old.

3. The atmosphere is sparse but hazy.
Pluto’s atmospheric pressure at the surface is about 0.001 percent that of Earth’s, a bit lower than expected. But New Horizons also spotted fog on the surface and a global haze that stretches up to 150 kilometers high.

4. Pluto and Charon are similar in density.
Astronomers believe that Pluto and its largest moon Charon formed in a giant impact like the one that produced Earth and the moon. Recent density measurements suggest that the two colliding bodies had similar compositions, offering insight into the planet-building material that was floating around during the solar system’s infancy.

5. Nix and Hydra are bright and wacky.
Objects in space tend to darken over time as they are pelted with radiation and dust, but these two Pluto moons are unexpectedly bright and probably covered in clean water ice. They are also spinning oddly, suggesting that Pluto and Charon are engaging in a gravitational tug-of-war on the smaller moons.

For its penultimate visit to the Saturnian moon Enceladus, the Cassini spacecraft will get hosed down by an alien ocean. On October 28, the probe will fly about 48 kilometers over the moon’s south pole and sample subsurface seawater that blasts through cracks in the ice. The measurements will help researchers figure out how suitable the seas of Enceladus are for extraterrestrial life.

Any hydrogen molecules detected within the fountains could confirm the presence of hydrothermal vents at the bottom of the ocean reported earlier this year. The spacecraft will also look for complex organic molecules carried aloft by the erupting water, though its instruments won’t be able to tell if the molecules come from aquatic aliens or not.

This is not Cassini’s first geyser dive, but it will be its last — and its deepest. The probe’s final visit to Enceladus will be on December 19, during which it will measure heat emanating from the ice cracks that etch across the moon’s south pole.

Just in time for the holiday shopping season, astronomers snagged a two-for-one deal on mysterious blasts of radio waves from other galaxies. An unprecedented double burst recently showed up along with four more of these flashes, researchers report online November 25 at arXiv.org.

Fast radio bursts, first detected in 2007, are bright blasts of radio energy that last for just a few milliseconds and are never seen again. Until now, astronomers had cataloged nine bursts that appeared to originate well outside the Milky Way. Yet, follow-up searches with nonradio telescopes for anything that might be pulsing or exploding keep coming up empty.

The five newcomers, detected at the Parkes radio telescope in Australia, follow the same pattern as all previous detected bursts with one exception — one flashed twice. Twin blasts separated by just 2.4 milliseconds came out of some sort of eruption that happened roughly 9 billion years ago in the constellation Octans, David Champion, an astronomer at the Max Planck Institute for Radio Astronomy in Bonn, Germany, and colleagues report.

A double flash rules out some ideas about what causes fast radio bursts. For instance, two neutron stars, dense cores left behind by dead massive stars, can collide only once. Rare vigorous blasts from pulsars might fit the bill, as would hyperflares from haphazard sources of gamma rays and X-rays known as “soft gamma repeaters,” possibly triggered by starquakes on highly magnetic neutron stars.

One small step for metal cubes, one giant leap for general relativity. On December 3 from a launchpad in French Guiana, the European Space Agency successfully launched the LISA Pathfinder mission, a satellite that will test technologies needed for a future space-based gravitational wave detector.

Ripples in spacetime generated by cataclysmic cosmic events have yet to be directly detected. Ground-based efforts such as Advanced LIGO are ongoing, but a detector in space would be much more sensitive. LISA Pathfinder will see if two test masses (cubes of a gold-platinum alloy) in free fall can maintain a 40-centimeter separation to an accuracy of 0.01 nanometers while encapsulated within a box that is orbiting a point between Earth and the sun. The ability to precisely control and measure distances between test masses is essential for sensing the subtle oscillations from gravitational waves.

Bright patches of salt on the dwarf planet Ceres hint at a subsurface layer of briny water ice. Ammonia-laden minerals also suggest that Ceres was at least partially assembled from material hauled in from the outskirts of the solar system, researchers report online December 9 in two papers in Nature.

Reflective spots on Ceres have been one of the enduring mysteries of the Dawn mission, which arrived at the dwarf planet March 6. During its visit, the spacecraft has cataloged more than 130 bright blemishes on Ceres’ surface. Image analysis now indicates that hydrated magnesium sulfates, a type of salt, blanket the brightest patches. Haze also appears over those same patches every morning (local time), probably from sublimation of dusty, briny water ice exposed by impacts with space rocks, Dawn scientists suggest.

While there is no evidence of water ice on the surface, spectra from Dawn show that the landscape is coated in ammoniated phyllosilicates. These minerals form in the presence of ammonia ice. In its current home in the asteroid belt, Ceres is now too close to the sun to freeze ammonia. But early in its life, Ceres might have grabbed ice-rich material drifting in from the outer solar system, the researchers suggest. Or Ceres might even have formed near the orbit of Neptune and subsequently wandered in after some nudging by the giant planets.

The New Horizons mission to Pluto might get all the attention, but 2015 had plenty of other amazing space mission firsts — and lasts, as scientists said good-bye to two orbiters.

Dawn
The Dawn probe arrived at Ceres March 6, becoming the first spacecraft to orbit a dwarf planet (take that, Pluto!). Dawn quickly started mapping its new home. Bright patches sitting within craters, which at first glance looked like exposed ice, are probably salt deposits. The craters themselves are also puzzlingly scattered unevenly across the surface.

Rosetta
A leak of oxygen, buried since the solar system’s start, was the last thing Rosetta mission researchers expected to detect at comet 67P/Churyumov-Gerasimenko. Finding such oxygen was a first in cometary chemistry. The Philae lander, meanwhile, surprised the world when it awoke June 13 from a nearly seven-month slumber. Contact has since been spotty.

Kepler
NASA’s premier planet hunter introduced us to Kepler 452b this year, possibly the most Earthlike world yet known. Its 385-day orbit of a sunlike star would be comforting to humans. But at 1.6 times the width of Earth, the exoplanet might not have a solid surface on which they could enjoy it. That’s OK. With 1,030 confirmed exoplanets and counting, the Kepler space telescope keeps looking.

MESSENGER
With a spectacular crash, the Mercury orbiter ended its four-year orbit April 30 when it ran out of fuel and smashed into the planet’s surface at over 14,000 kilo­meters per hour. One legacy: a new crater. MESSENGER was the first craft to orbit Mercury, to make complete maps and to spy water ice in the shadows at the planet’s poles.

Venus Express
The craft ran out of fuel late last year and began a death spiral into Venus’ atmosphere. It sent a final transmission to Earth in January, wrapping up nine years in orbit. But its data speak from beyond the grave. Flashes of infrared light from the planet’s surface add to evidence that volcanoes may be erupting there.

An unseen planet hiding in the outskirts of the solar system could explain orbital oddities among some of the sun’s far-flung icy bodies, Caltech planetary scientists Konstantin Batygin and Michael Brown suggest January 20 in Astronomical Journal. If such a world exists, it is roughly 10 times as massive as Earth. The potential planet saunters along a highly elongated orbit with an average distance from the sun between 400 to 1,500 times as far as Earth, they report.

That’s about 60 billion to 220 billion kilometers from the sun, for those keeping score.

The new simulations support suspicions of a ninth planet first voiced in March 2014, when researchers noticed that a dozen objects far beyond Neptune all crossed the midplane of the solar system at roughly the same spot as their closest approach to the sun. Interactions with the known giant planets should have randomized those crossings by now. The probability of such a clustering happening by chance is just 0.007 percent, the new study finds.

A planet patrolling the borderlands of the solar system, however, could keep all those orbits in place.

This study seems to “make this super-Earth sized planet a much more real possibility,” says Scott Sheppard, a planetary scientist at the Carnegie Institution for Science in Washington, D.C., who co-authored the 2014 paper.

Such a remote super-Earth probably originated closer to the sun only to be kicked out by the other giant planets during the solar system’s formative years, Batygin and Brown suggest.

When it comes to big balls of rock, exoplanet BD+20594b might have all other known worlds beat. At roughly half the diameter of Neptune, BD+20594b is 100 percent rock, researchers suggest online January 28 at arXiv.org. The planet seems to defy recent calculations that indicate a planet this large should be gassy.

BD+20594b sits about 500 light-years away in the constellation Aries. The planet is about 16 times as massive as Earth but just a little over twice as wide, making its density about 8 grams per cubic centimeter, Néstor Espinoza, an astrophysicist at the Pontifical Catholic University of Chile in Santiago, and colleagues report. Earth’s density, by comparison, is 5.5 grams per cubic centimeter. The new rocky planet was discovered in 2015 with the Kepler space telescope, which looks for the silhouettes of planets passing in front of their stars.

BD+20594b is comparable to Kepler 10c, a rocky “mega Earth” reported in 2014 to be 2.4 times as wide as Earth with a hefty mass (equal to about 17 Earths). Recent measurements indicate, however, that Kepler 10c isn’t quite as “mega” or as rocky as thought — only 14 times as massive as Earth — which means that the planet is probably encased in shell of gas or water.

A recently claimed home for an elusive cosmic radio burst might not be the host galaxy after all. What appeared to be an afterglow from the eruption might instead have been a run-of-the-mill radio emission from an unrelated galaxy, researchers claim online February 28 at arXiv.org.

Fast radio bursts, ephemeral blasts of radio waves that appear to originate in other galaxies, have been stumping astronomers since 2007. Identifying a host galaxy for an FRB could provide a clue to its cause. A recent FRB seemed to finally leave a return address. Two hours after the initial detection, astronomers caught a fading radio signal coming from the same direction. That signal led a team headed by Evan Keane, an astronomer with the Square Kilometer Array Organization in Macclesfield, England, to a galaxy about 6 billion light-years away.

But the claimed afterglow might have nothing to do with the FRB, Harvard University astronomers Peter Williams and Edo Berger suggest. A supermassive black hole appears to live in that galaxy, and it is actively feeding off a swirling disk of interstellar detritus. Such cosmic snacks routinely belch out radio waves. Observations of the galaxy obtained on February 26 and 27 at the Very Large Array in New Mexico show that not only has the “afterglow” returned, but it is brighter than what researchers saw in the hours after the FRB detection.

Williams and Berger argue that the galaxy is not the home of the FRB. But Duncan Lorimer, an astrophysicist at West Virginia University in Morgantown, says “I would be cautious about dismissing the result.” Astronomers don’t know what causes FRBs and many mysteries remain. One burst detected in 2012, for example, recently became the first FRB known to repeat itself after erupting 10 more times last year. It’s possible that this one repeats as well, Lorimer says. “It tells us how little we still know.”

Keane and colleagues are performing additional studies to better understand what’s going on. “When we've completed and fully considered those, we will certainly report our findings,” he says. “I know that FRBs are exciting, and appreciate that there is a lot interest, but we really can't rush the scientific process.”

That’s a lotta watts. And a lot more — 3.6 x 10 raised to 49 watts, or 36 septillion yottawatts — blasted out of the black hole collision that the Advanced Laser Interferometer Gravitational-Wave Observatory detected in September. Rather than a flash of light, the power came out as ripples in spacetime. As the black holes merged, three suns’ worth of mass transformed into gravitational wave energy in a few milliseconds, researchers report in Physical Review Letters on February 12.

“[It] created a violent storm in the fabric of space and time,” Caltech astrophysicist Kip Thorne said at a February news conference announcing the discovery. The storm’s power, he said, “was 50 times greater than all of the power put out by all of the stars in the universe put together.”
Source: Science News, Mar. 2016.

The last of a group of dense minerals that make up much of Earth’s crust and upper mantle has been found tucked inside a meteorite that slammed into Australia 135 years ago. The newly discovered mineral, a variety of majorite, is potentially abundant in sinking tectonic plates and could help illuminate the behavior of the deep Earth, its discoverers say.

Each identical component of this mineral contains 32 magnesium atoms, 32 silicon atoms and 96 oxygen atoms arranged in a distorted cube. Natural samples of MgSiO3 tetragonal garnet, the mineral’s scientific moniker, had eluded scientists since the mineral was first artificially produced in 1985.

Naotaka Tomioka, a mineralogist at the Kochi Institute for Core Sample Research in Japan, and colleagues discovered 0.5-micrometer-wide grains of the mineral in a slice of the 19th century meteorite. While many minerals found in meteorites form when slamming into Earth, the new mineral formed in space when two asteroids collided at a relative speed of about 2 kilometers per second, the researchers report online March 25 in Science Advances.

One challenge remains for the researchers: As discoverers of the mineral, they now get to name it.

Time to add another gorgeous space photo to the Hubble Space Telescope’s list of greatest hits. For the orbiting observatory’s 26th anniversary in space, astronomers snapped a picture of the Bubble Nebula, a seven-light-year-wide pocket of gas being blown away by a blazing massive star about 7,100 light-years away in the constellation Cassiopeia.

The star responsible for the bubble is young, just 4 million years old, and about 45 times as massive as our sun. It is so hot and bright that it launches its own gas into space at more than 6 million kilometers per hour. The vibrant colors in the nebula represent the elements oxygen, hydrogen and nitrogen.

Hubble launched April 24, 1990, aboard the space shuttle Discovery. A series of visits by astronauts have kept the aging telescope’s suite of cameras, spectrometers and ancillary equipment up-to-date and operating well into its third decade.

For about seven hours on Monday, May 9, the innermost planet will trek across the face of the sun and cast a shadow on our planet. During its journey, a rare event known as a transit, Mercury will appear as a tiny black speck on the sun. The transit will begin at 7:12 a.m. Eastern Daylight Time and end at 2:42 p.m. It will be visible from most countries, though folks in Japan, Australia, New Zealand, and islands in the West Pacific are out of luck.

Transits of Mercury happen on average about eight times a century and only in May or November. The last one was in 2006; the next one won’t be until 2019.

Don’t stare at the sun to try and see it. Seriously. Don’t do that. Staring at the sun is dangerous. Plus, Mercury is tiny. A solar-filtered telescope with at least 50x magnification is the best and safest way to enjoy the show. Many astronomy clubs and organizations will have viewing events. And there will be many ways to see it online such as NASA TV, the Virtual Telescope Project and the Slooh Observatory.

After nearly five years and 2.8 billion kilometers in space, NASA’s Juno probe — a mission to investigate Jupiter’s deep interior — has safely arrived at the giant planet.

Juno will spend the next 20 months orbiting Jupiter, figuring out how much water vapor hides beneath the clouds, mapping the planet’s internal structure and probing its vast magnetic field. The safe arrival makes Juno the ninth spacecraft to visit — and the second to orbit — the king of the planets.

Coming within 76,000 kilometers of Jupiter’s cloud tops (about one-fifth of the distance between Earth and the moon), Juno completed a 35-minute firing of its main engine at 11:05 p.m. Eastern. The maneuver slowed the spacecraft to around a mere 209,000 kilometers per hour, enough to be captured by Jupiter’s gravity.

All of the scientific instruments were switched off on June 29 as Juno slid into its first of 37 orbits, so there are no pictures to celebrate its arrival. Scientists won’t get their first intimate look at their quarry until Juno swoops in again on August 27, this time with all of its instruments operating.

After one more 53-day loop around Jupiter, Juno will start a series of 14-day orbits in October that will take the spacecraft over the north and south poles while soaring just 5,000 kilometers from the tops of the clouds that enshroud the planet.

The family of known dwarf planets orbiting the sun just got a new member. The tiny world, designated 2015 RR245, lives in the Kuiper belt, the icy debris field beyond Neptune that’s home to Pluto. RR245 is currently about 9.6 billion kilometers from the sun, or roughly 64 times as far as Earth, and it loops around the sun on an elongated orbit every 700 years or so.

Astronomers first noticed RR245 in February as a drifting speck of light in images taken last September at the Canada-France-Hawaii telescope in Hawaii. The planet’s size is hard to determine without knowing how reflective its surface is; it could be large and dark or tiny and bright. But if its surface is similar to other worlds in the Kuiper belt, then RR245 might be about 700 kilometers wide, just one-fifth the diameter of the moon.

Philae has been found, nestled in a shadowy crevice on comet 67P/Churyumov-Gerasimenko. The comet lander, lost since its tumultuous touch down on the comet on November 12, 2014, turned up in images taken by the Rosetta orbiter on September 2. Philae is on its side with one leg sticking out into sunlight. Its cockeyed posture most likely made it difficult for Philae to reliably get in touch with Rosetta, which explains why mission scientists had trouble re-establishing communication. The discovery comes about one month before the end of the Rosetta mission; the orbiter is scheduled to land on the comet on September 30 and then shut down.

Philae spent just a few days transmitting data from the surface of the comet. Its landing was rough, bouncing twice before stopping. Sitting in the shadow of a cliff, Philae was unable to use solar power to recharge its battery. Rosetta picked up intermittent communication in June and July 2015. Since January, temperatures on the comet have been too chilly for Philae’s electronics; mission scientists stopped listening for radio signals from the lander in July.
Source: Science News, Sep. 2016.

Jupiter’s moon Europa might once again be venting water into space, further supporting the idea that an ocean hides beneath its thick shell of ice, researchers reported September 26 at a news conference.

Plumes erupting from the moon’s surface, silhouetted against background light from Jupiter, appear in several images taken by the Hubble Space Telescope in early 2014. The geysers — presumably of water vapor or ice particles — showed up in the same location as an eruption captured by Hubble in 2012. The eruptions also appear to be intermittent, appearing in only three out of 10 images. Material hovering over the moon’s southern hemisphere and absorbing ultraviolet light coming from Jupiter made the plumes visible.

“The plumes are a sign that we may be able to explore the ocean without having to drill through unknown miles of ice,” said William Sparks, an astronomer at the Space Telescope Science Institute in Baltimore. “We presume it to be water or ice particles because that’s what Europa is made of and those molecules do absorb at the wavelengths we observed,” he said. Future spacecraft could plow through the plumes and sample the water to better understand its chemistry and look for by-products of life.

Two trillion galaxies. That’s the latest estimate for the number of galaxies that live — or have lived — in the observable universe, researchers report online October 10 at arXiv.org. This updated headcount is roughly 10 times greater than previous estimates and suggests that there are a lot more galaxies out there for future telescopes to explore.

Hordes of relatively tiny galaxies, weighing as little as 1 million suns, are responsible for most of this tweak to the cosmic census. Astronomers haven’t directly seen these galaxies yet. Christopher Conselice, an astrophysicist at the University of Nottingham in England, and colleagues combined data from many ground- and space-based telescopes to look at how the number of galaxies in a typical volume of the universe has changed over much of cosmic history. They then calculated how many galaxies have come and gone in the universe.

The galactic population has dwindled over time, as most of those 2 trillion galaxies collided and merged to build larger galaxies such as the Milky Way, the researchers suggest. That’s in line with prevailing ideas about how massive galaxies have been assembled. Seeing many of these remote runts, however, is beyond the ability of even the next generation of telescopes. “We will have to wait at least several decades before even the majority of galaxies have basic imaging,” the researchers write.

The moon is one tough satellite. With no atmosphere, it endures a barrage of incoming asteroids and comets that pit its surface with a constellation of craters. A new map (above) reveals 222 recent impact craters, 33 percent more than simulations predicted. Scientists spotted the features by analyzing about 14,000 pairs of before-and-after images captured by the Lunar Reconnaissance Orbiter from 2009 to 2015.

The craters — up to 43 meters in diameter — were probably formed by small meteoroids crashing into the crust. Using the image pairs, the researchers created ratio images, which highlight how the impacts alter the reflectance of the moon’s surface.

The scientists also found about 47,000 “splotches,” faint marks several to tens of meters across. Most result from secondary debris being jettisoned by impacts and spattering the surface, the researchers propose in the Oct. 13 Nature.

Those splotches would “churn” the upper two centimeters of lunar soil in about 81,000 years, more than 100 times faster than previous predictions that didn’t include the smudges, researchers say. That revelation could improve interpretations of remote-sensing data and help engineers design equipment to better withstand the occasional speckling of soil, says study coauthor Mark Robinson, a planetary geologist at Arizona State University in Tempe. “All of the images we’re taking … and the discoveries we’re making are feeding forward into future human exploration of the moon,” he says.

Giant gathering of galaxies discovered hiding on far side of Milky Way

An immense wall of galaxies, stretching over 380 million light-years, is hiding beyond the far side of the Milky Way.

Dubbed the Vela supercluster, this galactic horde sits about 800 million light-years away in the constellation Vela, researchers report online November 8 in Monthly Notices of the Royal Astronomical Society Letters. Despite its size and relative proximity, Vela has gone unnoticed because it is largely obscured by our own galaxy.

Superclusters — assemblages of groups of galaxies — are among the largest known structures in the universe. Following up on earlier hints that an uncharted supercluster might lurk nearby, Renée Kraan-Korteweg, an astronomer at the University of Cape Town in South Africa, and colleagues scoured a patch of sky bisected by a wall of stars that is part of the Milky Way. Using telescopes in South Africa and Australia, they measured distances to 4,432 galaxies and found that many, to the north and south of the wall, appear to be clumped together.

Vela could help solve a long-standing mystery. The Milky Way and dozens of other galaxies in the immediate neighborhood move together through space. Gravity from known superclusters can account for some of that motion, but not all of it. Astronomers don’t yet know the mass — and hence the gravitational influence — of Vela, but it could be partly responsible for nudging us along.

A chatty source of radio waves from deep space has a little more to say. Six more blasts of radio energy, each lasting just a few milliseconds, erupted from some phenomenon outside of our galaxy, researchers report in the Dec. 20 Astrophysical Journal. This detection follows 11 previously recorded outbursts of radio waves from the same location, the only known repeater in a class of enigmatic eruptions known as fast radio bursts.

The origins of these radio bursts, 18 of which have been reported since 2007, are an ongoing puzzle. The continuing barrage from this repeating source, roughly 3 billion light-years away in the constellation Auriga, implies that whatever is causing some radio bursts is not a one-time destructive event such as a collision or explosion. Flares from a young neutron star, the dense core left behind after a massive star explodes, are a promising candidate.

The latest volley was detected in late 2015, Paul Scholz, a graduate student at McGill University in Montreal, and colleagues report. Five blasts were recorded at the Green Bank Telescope in West Virginia and one at Arecibo Observatory in Puerto Rico. This object was first detected at Arecibo in 2012. Ten more blasts followed in May and June 2015.

With scorching temperatures and a mind-numbingly slow rotation (one Venus day lasts 243 Earth days), Venus was already a contender for weirdest planet in the solar system. Now add a giant arc-shaped structure to its list of oddities. The mysterious 10,000-kilometer-long structure was so big that it appeared to stretch between the planet’s poles. And it didn’t budge, even as winds in the planet’s upper atmosphere whipped along at a brisk 100 meters per second.

The C-shaped structure, which lasted at least four Earth days, could be a gravity wave, a large disturbance in the flow of a fluid or air, scientists say. It may have formed on Venus when winds in the planet’s lower atmosphere slammed into a mountain range and were pushed into the upper atmosphere, where it got stuck, a team of Japanese researchers report January 16 in Nature Geoscience.

Captured in images taken by JAXA’s Akatsuki spacecraft in December 2015, the structure could be the largest stationary gravity wave ever observed in the solar system. If it did shift from the lower to upper atmosphere, there may be more going on near the surface of the planet than scientists previously thought.

WASHINGTON — Researchers have devised a test to see if pairs of black holes — famous for creating gravitational waves when they merge — themselves formed from multiple mergers of smaller black holes.

The Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO, has detected spacetime ripples from two sets of merging black holes. Scientists typically assume that such black holes formed in the collapse of a massive star. But in especially crowded patches of the universe, black holes could have formed over generations of unions, astrophysicist Maya Fishbach of the University of Chicago explained January 28 at a meeting of the American Physical Society. Or the merging cycle could have occurred in the very early universe, starting with primordial black holes — objects that may have formed when extremely dense pockets of matter directly collapsed.

Fishbach and colleagues studied how quickly black holes whirl around. In simulations, black holes that repeatedly merged reached a high rate of spin, the scientists found. That result didn’t depend on certain properties of the initial black holes, like whether they were spinning to begin with or not. “It’s cool,” says Fishbach. “The predictions from this in terms of spin are very robust,” making the idea easy to test.

So far, the spins of LIGO’s black holes are lower than the predictions. If the multiple merging process occurs, it could be very rare, so to conclusively test the idea would require tens to hundreds of black hole detections, Fishbach says.

The planet KELT 9b is so hot — hotter than many stars — that it shatters gas giant temperature records, researchers report online June 5 in Nature.
This Jupiter-like exoplanet revolves around a star just 650 light-years away, locked in an orbit that keeps one side always facing its star. With blistering temps hovering at about 4,300o Celsius, the atmosphere on KELT 9b’s dayside is over 700 degrees hotter than the previous record-holder — and hot enough that atoms cannot bind together to form molecules.
“It’s like a star-planet hybrid,” says Drake Deming, a planetary scientist at the University of Maryland in College Park who was not involved in the research. “A kind of object we’ve never seen before.”
KELT 9b also boasts an unusual orbit, travelling around the poles of its star, rather than the equator, once every 36 hours. And radiation from KELT 9b’s host star is so intense that it blows the planet’s atmosphere out like a comet tail — and may eventually strip it away completely.
The planet is so bizarre that it took scientists nearly three years to convince themselves it was real, says Scott Gaudi of Ohio State University. Deming suspects KELT 9b is “the tip of the iceberg” for an undiscovered population of scalding-hot gas giants.

The most distant star ever observed has been spotted, and its light comes from across two-thirds of the universe. That puts the star a whopping 9 billion light-years away.

Patrick Kelly at the University of California, Berkeley and his colleagues found the star in Hubble Space Telescope images of a galaxy cluster called MACS J1149. In April and May 2016, Kelly and his team saw a mysteriously fluctuating point of light in the galaxy cluster’s vicinity.

Follow-up images and analyses, posted June 30 at arXiv.org, showed that light is probably from a single bright blue star that coincidentally was behind the galaxy cluster, aligned along Hubble’s line of sight. The star is visible because the galaxy cluster’s gravity bent spacetime around the cluster, making it act like a cosmic magnifying glass. This phenomenon, called gravitational lensing, helps astronomers observe objects more distant than telescopes can see on their own.

The team calculated how much the star’s light was stretched by its journey, which was a clue to its extreme distance. Since the universe is 13.8 billion years old, that means this star’s light has crossed 65 percent of the universe to reach us. The previous farthest star observed directly was just 55 million light-years away.